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NetBSD/lib/libpcap/gencode.c
itojun 317eb9acd4 compile without INET6. PR 13080
2001-06-01 15:49:53 +00:00

3037 lines
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/* $NetBSD: gencode.c,v 1.29 2001/06/01 15:49:53 itojun Exp $ */
/*
* Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static const char rcsid[] =
"@(#) Header: gencode.c,v 1.93 97/06/12 14:22:47 leres Exp (LBL)";
#else
__RCSID("$NetBSD: gencode.c,v 1.29 2001/06/01 15:49:53 itojun Exp $");
#endif
#endif
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/time.h>
#if __STDC__
struct mbuf;
struct rtentry;
#endif
#include <net/if.h>
#include <netinet/in.h>
#ifdef __NetBSD__
#include <net/if_arc.h>
#include <net/if_ether.h>
#else
#include <netinet/if_ether.h>
#endif
#include <stdlib.h>
#include <memory.h>
#include <setjmp.h>
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#include "pcap-int.h"
#include "ethertype.h"
#include "gencode.h"
#include "ppp.h"
#include <pcap-namedb.h>
#ifdef INET6
#include <netdb.h>
#include <sys/socket.h>
#endif /*INET6*/
#include "gnuc.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#define JMP(c) ((c)|BPF_JMP|BPF_K)
/* Locals */
static jmp_buf top_ctx;
static pcap_t *bpf_pcap;
/* XXX */
#ifdef PCAP_FDDIPAD
int pcap_fddipad = PCAP_FDDIPAD;
#else
int pcap_fddipad;
#endif
/* VARARGS */
__dead void
#if __STDC__
bpf_error(const char *fmt, ...)
#else
bpf_error(fmt, va_alist)
const char *fmt;
va_dcl
#endif
{
va_list ap;
#if __STDC__
va_start(ap, fmt);
#else
va_start(ap);
#endif
if (bpf_pcap != NULL)
(void)vsnprintf(pcap_geterr(bpf_pcap),
PCAP_ERRBUF_SIZE, fmt, ap);
va_end(ap);
longjmp(top_ctx, 1);
/* NOTREACHED */
}
static void init_linktype(int);
static int alloc_reg(void);
static void free_reg(int);
static struct block *root;
/*
* We divy out chunks of memory rather than call malloc each time so
* we don't have to worry about leaking memory. It's probably
* not a big deal if all this memory was wasted but it this ever
* goes into a library that would probably not be a good idea.
*/
#define NCHUNKS 16
#define CHUNK0SIZE 1024
struct chunk {
u_int n_left;
void *m;
};
static struct chunk chunks[NCHUNKS];
static int cur_chunk;
static void *newchunk(u_int);
static void freechunks(void);
static inline struct block *new_block(int);
static inline struct slist *new_stmt(int);
static struct block *gen_retblk(int);
static inline void syntax(void);
static void backpatch(struct block *, struct block *);
static void merge(struct block *, struct block *);
static struct block *gen_cmp(u_int, u_int, bpf_int32);
static struct block *gen_mcmp(u_int, u_int, bpf_int32, bpf_u_int32);
static struct block *gen_bcmp(u_int, u_int, const u_char *);
static struct block *gen_uncond(int);
static inline struct block *gen_true(void);
static inline struct block *gen_false(void);
static struct block *gen_linktype(int);
static struct block *gen_hostop(bpf_u_int32, bpf_u_int32, int, int, u_int, u_int);
#ifdef INET6
static struct block *gen_hostop6(struct in6_addr *, struct in6_addr *, int, int, u_int, u_int);
#endif
static struct block *gen_ahostop(const u_char *, int);
static struct block *gen_ehostop(const u_char *, int);
static struct block *gen_fhostop(const u_char *, int);
static struct block *gen_dnhostop(bpf_u_int32, int, u_int);
static struct block *gen_host(bpf_u_int32, bpf_u_int32, int, int);
#ifdef INET6
static struct block *gen_host6(struct in6_addr *, struct in6_addr *, int, int);
#endif
#ifndef INET6
static struct block *gen_gateway(const u_char *, bpf_u_int32 **, int, int);
#endif
static struct block *gen_ipfrag(void);
static struct block *gen_portatom(int, bpf_int32);
#ifdef INET6
static struct block *gen_portatom6(int, bpf_int32);
#endif
struct block *gen_portop(int, int, int);
static struct block *gen_port(int, int, int);
#ifdef INET6
struct block *gen_portop6(int, int, int);
static struct block *gen_port6(int, int, int);
#endif
static int lookup_proto(const char *, int);
static struct block *gen_protochain(int, int, int);
static struct block *gen_proto(int, int, int);
static struct slist *xfer_to_x(struct arth *);
static struct slist *xfer_to_a(struct arth *);
static struct block *gen_len(int, int);
static void *
newchunk(n)
u_int n;
{
struct chunk *cp;
int k, size;
/* XXX Round to structure boundary. */
n = ALIGN(n);
cp = &chunks[cur_chunk];
if (n > cp->n_left) {
++cp, k = ++cur_chunk;
if (k >= NCHUNKS)
bpf_error("out of memory");
size = CHUNK0SIZE << k;
cp->m = (void *)malloc(size);
memset((char *)cp->m, 0, size);
cp->n_left = size;
if (n > size)
bpf_error("out of memory");
}
cp->n_left -= n;
return (void *)((char *)cp->m + cp->n_left);
}
static void
freechunks()
{
int i;
cur_chunk = 0;
for (i = 0; i < NCHUNKS; ++i)
if (chunks[i].m != NULL) {
free(chunks[i].m);
chunks[i].m = NULL;
}
}
/*
* A strdup whose allocations are freed after code generation is over.
*/
char *
sdup(s)
register const char *s;
{
int n = strlen(s) + 1;
char *cp = newchunk(n);
strcpy(cp, s); /* XXX strcpy is safe */
return (cp);
}
static inline struct block *
new_block(code)
int code;
{
struct block *p;
p = (struct block *)newchunk(sizeof(*p));
p->s.code = code;
p->head = p;
return p;
}
static inline struct slist *
new_stmt(code)
int code;
{
struct slist *p;
p = (struct slist *)newchunk(sizeof(*p));
p->s.code = code;
return p;
}
static struct block *
gen_retblk(v)
int v;
{
struct block *b = new_block(BPF_RET|BPF_K);
b->s.k = v;
return b;
}
static inline void
syntax()
{
bpf_error("syntax error in filter expression");
}
static bpf_u_int32 netmask;
static int snaplen;
int no_optimize;
extern int n_errors;
int
pcap_compile(pcap_t *p, struct bpf_program *program,
char *buf, int optimize, bpf_u_int32 mask)
{
int len;
no_optimize = 0;
n_errors = 0;
root = NULL;
bpf_pcap = p;
if (setjmp(top_ctx)) {
freechunks();
return (-1);
}
netmask = mask;
snaplen = pcap_snapshot(p);
lex_init(buf ? buf : "");
init_linktype(pcap_datalink(p));
(void)pcap_parse();
if (n_errors)
syntax();
if (root == NULL)
root = gen_retblk(snaplen);
if (optimize && !no_optimize) {
bpf_optimize(&root);
if (root == NULL ||
(root->s.code == (BPF_RET|BPF_K) && root->s.k == 0))
bpf_error("expression rejects all packets");
}
program->bf_insns = icode_to_fcode(root, &len);
program->bf_len = len;
freechunks();
return (0);
}
/*
* entry point for using the compiler with no pcap open
* pass in all the stuff that is needed explicitly instead.
*/
int
pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
struct bpf_program *program,
char *buf, int optimize, bpf_u_int32 mask, char *errbuf)
{
pcap_t p;
int len;
memset(&p, 0, sizeof(p));
no_optimize = 0;
n_errors = 0;
root = NULL;
bpf_pcap = &p;
if (setjmp(top_ctx)) {
strncpy(errbuf, pcap_geterr(&p), PCAP_ERRBUF_SIZE - 1);
freechunks();
return (-1);
}
netmask = mask;
snaplen = snaplen_arg; /* basis of filter match return value */
lex_init(buf ? buf : "");
init_linktype(linktype_arg);
(void)pcap_parse();
if (n_errors)
syntax();
if (root == NULL)
root = gen_retblk(snaplen_arg);
if (optimize && !no_optimize) {
bpf_optimize(&root);
if (root == NULL ||
(root->s.code == (BPF_RET|BPF_K) && root->s.k == 0))
bpf_error("expression rejects all packets");
}
program->bf_insns = icode_to_fcode(root, &len);
program->bf_len = len;
freechunks();
return (0);
}
/*
* Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
* which of the jt and jf fields has been resolved and which is a pointer
* back to another unresolved block (or nil). At least one of the fields
* in each block is already resolved.
*/
static void
backpatch(list, target)
struct block *list, *target;
{
struct block *next;
while (list) {
if (!list->sense) {
next = JT(list);
JT(list) = target;
} else {
next = JF(list);
JF(list) = target;
}
list = next;
}
}
/*
* Merge the lists in b0 and b1, using the 'sense' field to indicate
* which of jt and jf is the link.
*/
static void
merge(b0, b1)
struct block *b0, *b1;
{
register struct block **p = &b0;
/* Find end of list. */
while (*p)
p = !((*p)->sense) ? &JT(*p) : &JF(*p);
/* Concatenate the lists. */
*p = b1;
}
void
finish_parse(p)
struct block *p;
{
backpatch(p, gen_retblk(snaplen));
p->sense = !p->sense;
backpatch(p, gen_retblk(0));
root = p->head;
}
void
gen_and(b0, b1)
struct block *b0, *b1;
{
backpatch(b0, b1->head);
b0->sense = !b0->sense;
b1->sense = !b1->sense;
merge(b1, b0);
b1->sense = !b1->sense;
b1->head = b0->head;
}
void
gen_or(b0, b1)
struct block *b0, *b1;
{
b0->sense = !b0->sense;
backpatch(b0, b1->head);
b0->sense = !b0->sense;
merge(b1, b0);
b1->head = b0->head;
}
void
gen_not(b)
struct block *b;
{
b->sense = !b->sense;
}
static struct block *
gen_cmp(offset, size, v)
u_int offset, size;
bpf_int32 v;
{
struct slist *s;
struct block *b;
s = new_stmt(BPF_LD|BPF_ABS|size);
s->s.k = offset;
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
b->s.k = v;
return b;
}
static struct block *
gen_mcmp(offset, size, v, mask)
u_int offset, size;
bpf_int32 v;
bpf_u_int32 mask;
{
struct block *b = gen_cmp(offset, size, v);
struct slist *s;
if (mask != 0xffffffff) {
s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
s->s.k = mask;
b->stmts->next = s;
}
return b;
}
static struct block *
gen_bcmp(offset, size, v)
register u_int offset, size;
register const u_char *v;
{
register struct block *b, *tmp;
b = NULL;
while (size >= 4) {
register const u_char *p = &v[size - 4];
bpf_int32 w = ((bpf_int32)p[0] << 24) |
((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3];
tmp = gen_cmp(offset + size - 4, BPF_W, w);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
size -= 4;
}
while (size >= 2) {
register const u_char *p = &v[size - 2];
bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1];
tmp = gen_cmp(offset + size - 2, BPF_H, w);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
size -= 2;
}
if (size > 0) {
tmp = gen_cmp(offset, BPF_B, (bpf_int32)v[0]);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
}
return b;
}
/*
* Various code constructs need to know the layout of the data link
* layer. These variables give the necessary offsets. off_linktype
* is set to -1 for no encapsulation, in which case the check is then
* deferred to linktype_af. If that is AF_UNSPEC, AF_INET and AF_INET6
* are allowed, for backwards compatibility. Otherwise, it is the
* family to expect.
*/
static u_int off_linktype;
static u_int off_nl;
static int linktype;
static int linktype_af;
static void
init_linktype(type)
int type;
{
linktype = type;
if (DLT_IS_RAWAF(type)) {
off_linktype = -1;
off_nl = 0;
linktype_af = DLT_RAWAF_AF(type);
return;
}
switch (type) {
case DLT_ARCNET:
off_linktype = 2;
off_nl = 6; /* XXX in reality, variable! */
return;
case DLT_EN10MB:
off_linktype = 12;
off_nl = 14;
return;
case DLT_SLIP:
/*
* SLIP doesn't have a link level type. The 16 byte
* header is hacked into our SLIP driver.
*/
off_linktype = -1;
off_nl = 16;
linktype_af = AF_INET;
return;
case DLT_SLIP_BSDOS:
/* XXX this may be the same as the DLT_PPP_BSDOS case */
off_linktype = -1;
/* XXX end */
off_nl = 24;
return;
case DLT_NULL:
off_linktype = 0;
off_nl = 4;
return;
case DLT_PPP:
off_linktype = 2;
off_nl = 4;
return;
case DLT_PPP_BSDOS:
off_linktype = 5;
off_nl = 24;
return;
case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */
off_linktype = 2;
off_nl = 4;
return;
case DLT_PPP_ETHER:
/*
* This does no include the Ethernet header, and
* only covers session state.
*/
off_linktype = 6;
off_nl = 8;
return;
case DLT_FDDI:
/*
* FDDI doesn't really have a link-level type field.
* We assume that SSAP = SNAP is being used and pick
* out the encapsulated Ethernet type.
*/
off_linktype = 19;
#ifdef PCAP_FDDIPAD
off_linktype += pcap_fddipad;
#endif
off_nl = 21;
#ifdef PCAP_FDDIPAD
off_nl += pcap_fddipad;
#endif
return;
case DLT_IEEE802:
off_linktype = 20;
off_nl = 22;
return;
case DLT_ATM_RFC1483:
/*
* assume routed, non-ISO PDUs
* (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
*/
off_linktype = 6;
off_nl = 8;
return;
case DLT_HDLC:
off_linktype = 2;
off_nl = 4;
return;
case DLT_RAW:
off_linktype = -1;
off_nl = 0;
linktype_af = AF_UNSPEC;
return;
}
bpf_error("libpcap: unknown data link type 0x%x", linktype);
/* NOTREACHED */
}
static struct block *
gen_uncond(rsense)
int rsense;
{
struct block *b;
struct slist *s;
s = new_stmt(BPF_LD|BPF_IMM);
s->s.k = !rsense;
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
return b;
}
static inline struct block *
gen_true()
{
return gen_uncond(1);
}
static inline struct block *
gen_false()
{
return gen_uncond(0);
}
static struct block *
gen_linktype(proto)
register int proto;
{
struct block *b0, *b1;
/*
* If we're not using encapsulation, compare the proto against
* the one we're expecting.
*
* Note: this catches the RAWAF case.
*/
if (off_linktype == -1) {
switch (linktype_af) {
case AF_UNSPEC:
if (proto == ETHERTYPE_IP)
return gen_true();
#ifdef INET6
/*
* This isn't the right thing to do, but sometimes
* it is necessary.
*/
if (proto == ETHERTYPE_IPV6)
return gen_true();
#endif
break;
case AF_INET:
if (proto == ETHERTYPE_IP)
return gen_true();
else
return gen_false();
break;
#ifdef INET6
case AF_INET6:
if (proto == ETHERTYPE_IPV6)
return gen_true();
else
return gen_false();
break;
#endif
}
}
switch (linktype) {
case DLT_SLIP:
return gen_false();
case DLT_PPP:
case DLT_PPP_SERIAL:
case DLT_PPP_ETHER:
if (proto == ETHERTYPE_IP)
proto = PPP_IP;
#ifdef INET6
else if (proto == ETHERTYPE_IPV6)
proto = PPP_IPV6;
#endif /* INET6 */
break;
case DLT_PPP_BSDOS:
switch (proto) {
case ETHERTYPE_IP:
b0 = gen_cmp(off_linktype, BPF_H, PPP_IP);
b1 = gen_cmp(off_linktype, BPF_H, PPP_VJC);
gen_or(b0, b1);
b0 = gen_cmp(off_linktype, BPF_H, PPP_VJNC);
gen_or(b1, b0);
return b0;
#ifdef INET6
case ETHERTYPE_IPV6:
proto = PPP_IPV6;
/* more to go? */
break;
#endif /* INET6 */
case ETHERTYPE_DN:
proto = PPP_DECNET;
break;
case ETHERTYPE_ATALK:
proto = PPP_APPLE;
break;
case ETHERTYPE_NS:
proto = PPP_NS;
break;
}
break;
case DLT_NULL:
switch (proto) {
case ETHERTYPE_IP:
return (gen_cmp(0, BPF_W, (bpf_int32)htonl(AF_INET)));
break;
#ifdef INET6
case ETHERTYPE_IPV6:
return (gen_cmp(0, BPF_W, (bpf_int32)htonl(AF_INET6)));
break;
#endif
default:
return gen_false();
}
break;
case DLT_ARCNET:
/*
* XXX should we check for first fragment if the protocol
* uses PHDS?
*/
switch(proto) {
default:
return gen_false();
#ifdef INET6
case ETHERTYPE_IPV6:
return(gen_cmp(2, BPF_B,
(bpf_int32)htonl(ARCTYPE_INET6)));
#endif /* INET6 */
case ETHERTYPE_IP:
b0 = gen_cmp(2, BPF_B, (bpf_int32)htonl(ARCTYPE_IP));
b1 = gen_cmp(2, BPF_B,
(bpf_int32)htonl(ARCTYPE_IP_OLD));
gen_or(b0, b1);
return(b1);
case ETHERTYPE_ARP:
b0 = gen_cmp(2, BPF_B, (bpf_int32)htonl(ARCTYPE_ARP));
b1 = gen_cmp(2, BPF_B,
(bpf_int32)htonl(ARCTYPE_ARP_OLD));
gen_or(b0, b1);
return(b1);
case ETHERTYPE_REVARP:
return(gen_cmp(2, BPF_B,
(bpf_int32)htonl(ARCTYPE_REVARP)));
case ETHERTYPE_ATALK:
return(gen_cmp(2, BPF_B,
(bpf_int32)htonl(ARCTYPE_ATALK)));
}
}
return gen_cmp(off_linktype, BPF_H, (bpf_int32)proto);
}
static struct block *
gen_hostop(addr, mask, dir, proto, src_off, dst_off)
bpf_u_int32 addr;
bpf_u_int32 mask;
int dir, proto;
u_int src_off, dst_off;
{
struct block *b0, *b1;
u_int offset;
switch (dir) {
case Q_SRC:
offset = src_off;
break;
case Q_DST:
offset = dst_off;
break;
case Q_AND:
b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
gen_or(b0, b1);
return b1;
default:
abort();
}
b0 = gen_linktype(proto);
b1 = gen_mcmp(offset, BPF_W, (bpf_int32)addr, mask);
gen_and(b0, b1);
return b1;
}
#ifdef INET6
static struct block *
gen_hostop6(addr, mask, dir, proto, src_off, dst_off)
struct in6_addr *addr;
struct in6_addr *mask;
int dir, proto;
u_int src_off, dst_off;
{
struct block *b0, *b1;
u_int offset;
u_int32_t *a, *m;
switch (dir) {
case Q_SRC:
offset = src_off;
break;
case Q_DST:
offset = dst_off;
break;
case Q_AND:
b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
gen_or(b0, b1);
return b1;
default:
abort();
}
/* this order is important */
a = (u_int32_t *)addr;
m = (u_int32_t *)mask;
b1 = gen_mcmp(offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
b0 = gen_mcmp(offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
gen_and(b0, b1);
b0 = gen_mcmp(offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
gen_and(b0, b1);
b0 = gen_mcmp(offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
gen_and(b0, b1);
b0 = gen_linktype(proto);
gen_and(b0, b1);
return b1;
}
#endif /*INET6*/
static struct block *
gen_ehostop(eaddr, dir)
register const u_char *eaddr;
register int dir;
{
register struct block *b0, *b1;
switch (dir) {
case Q_SRC:
return gen_bcmp(6, 6, eaddr);
case Q_DST:
return gen_bcmp(0, 6, eaddr);
case Q_AND:
b0 = gen_ehostop(eaddr, Q_SRC);
b1 = gen_ehostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ehostop(eaddr, Q_SRC);
b1 = gen_ehostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
}
abort();
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for DLT_FDDI
*/
static struct block *
gen_fhostop(eaddr, dir)
register const u_char *eaddr;
register int dir;
{
struct block *b0, *b1;
switch (dir) {
case Q_SRC:
#ifdef PCAP_FDDIPAD
return gen_bcmp(6 + 1 + pcap_fddipad, 6, eaddr);
#else
return gen_bcmp(6 + 1, 6, eaddr);
#endif
case Q_DST:
#ifdef PCAP_FDDIPAD
return gen_bcmp(0 + 1 + pcap_fddipad, 6, eaddr);
#else
return gen_bcmp(0 + 1, 6, eaddr);
#endif
case Q_AND:
b0 = gen_fhostop(eaddr, Q_SRC);
b1 = gen_fhostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_fhostop(eaddr, Q_SRC);
b1 = gen_fhostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
}
abort();
/* NOTREACHED */
}
/*
* This is quite tricky because there may be pad bytes in front of the
* DECNET header, and then there are two possible data packet formats that
* carry both src and dst addresses, plus 5 packet types in a format that
* carries only the src node, plus 2 types that use a different format and
* also carry just the src node.
*
* Yuck.
*
* Instead of doing those all right, we just look for data packets with
* 0 or 1 bytes of padding. If you want to look at other packets, that
* will require a lot more hacking.
*
* To add support for filtering on DECNET "areas" (network numbers)
* one would want to add a "mask" argument to this routine. That would
* make the filter even more inefficient, although one could be clever
* and not generate masking instructions if the mask is 0xFFFF.
*/
static struct block *
gen_dnhostop(addr, dir, base_off)
bpf_u_int32 addr;
int dir;
u_int base_off;
{
struct block *b0, *b1, *b2, *tmp;
u_int offset_lh; /* offset if long header is received */
u_int offset_sh; /* offset if short header is received */
switch (dir) {
case Q_DST:
offset_sh = 1; /* follows flags */
offset_lh = 7; /* flgs,darea,dsubarea,HIORD */
break;
case Q_SRC:
offset_sh = 3; /* follows flags, dstnode */
offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */
break;
case Q_AND:
/* Inefficient because we do our Calvinball dance twice */
b0 = gen_dnhostop(addr, Q_SRC, base_off);
b1 = gen_dnhostop(addr, Q_DST, base_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
/* Inefficient because we do our Calvinball dance twice */
b0 = gen_dnhostop(addr, Q_SRC, base_off);
b1 = gen_dnhostop(addr, Q_DST, base_off);
gen_or(b0, b1);
return b1;
default:
abort();
}
b0 = gen_linktype(ETHERTYPE_DN);
/* Check for pad = 1, long header case */
tmp = gen_mcmp(base_off + 2, BPF_H,
(bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF));
b1 = gen_cmp(base_off + 2 + 1 + offset_lh,
BPF_H, (bpf_int32)ntohs(addr));
gen_and(tmp, b1);
/* Check for pad = 0, long header case */
tmp = gen_mcmp(base_off + 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7);
b2 = gen_cmp(base_off + 2 + offset_lh, BPF_H, (bpf_int32)ntohs(addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Check for pad = 1, short header case */
tmp = gen_mcmp(base_off + 2, BPF_H,
(bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF));
b2 = gen_cmp(base_off + 2 + 1 + offset_sh,
BPF_H, (bpf_int32)ntohs(addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Check for pad = 0, short header case */
tmp = gen_mcmp(base_off + 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7);
b2 = gen_cmp(base_off + 2 + offset_sh, BPF_H, (bpf_int32)ntohs(addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Combine with test for linktype */
gen_and(b0, b1);
return b1;
}
static struct block *
gen_host(addr, mask, proto, dir)
bpf_u_int32 addr;
bpf_u_int32 mask;
int proto;
int dir;
{
struct block *b0, *b1;
switch (proto) {
case Q_DEFAULT:
b0 = gen_host(addr, mask, Q_IP, dir);
b1 = gen_host(addr, mask, Q_ARP, dir);
gen_or(b0, b1);
b0 = gen_host(addr, mask, Q_RARP, dir);
gen_or(b1, b0);
return b0;
case Q_IP:
return gen_hostop(addr, mask, dir, ETHERTYPE_IP,
off_nl + 12, off_nl + 16);
case Q_RARP:
return gen_hostop(addr, mask, dir, ETHERTYPE_REVARP,
off_nl + 14, off_nl + 24);
case Q_ARP:
return gen_hostop(addr, mask, dir, ETHERTYPE_ARP,
off_nl + 14, off_nl + 24);
case Q_TCP:
bpf_error("'tcp' modifier applied to host");
case Q_UDP:
bpf_error("'udp' modifier applied to host");
case Q_ICMP:
bpf_error("'icmp' modifier applied to host");
case Q_IGMP:
bpf_error("'igmp' modifier applied to host");
case Q_IGRP:
bpf_error("'igrp' modifier applied to host");
case Q_PIM:
bpf_error("'pim' modifier applied to host");
case Q_VRRP:
bpf_error("'vrrp' modifier applied to host");
case Q_ATALK:
bpf_error("ATALK host filtering not implemented");
case Q_DECNET:
return gen_dnhostop(addr, dir, off_nl);
case Q_SCA:
bpf_error("SCA host filtering not implemented");
case Q_LAT:
bpf_error("LAT host filtering not implemented");
case Q_MOPDL:
bpf_error("MOPDL host filtering not implemented");
case Q_MOPRC:
bpf_error("MOPRC host filtering not implemented");
#ifdef INET6
case Q_IPV6:
bpf_error("'ip6' modifier applied to ip host");
case Q_ICMPV6:
bpf_error("'icmp6' modifier applied to host");
#endif /* INET6 */
case Q_AH:
bpf_error("'ah' modifier applied to host");
case Q_ESP:
bpf_error("'esp' modifier applied to host");
default:
abort();
}
/* NOTREACHED */
}
#ifdef INET6
static struct block *
gen_host6(addr, mask, proto, dir)
struct in6_addr *addr;
struct in6_addr *mask;
int proto;
int dir;
{
switch (proto) {
case Q_DEFAULT:
return gen_host6(addr, mask, Q_IPV6, dir);
case Q_IP:
bpf_error("'ip' modifier applied to ip6 host");
case Q_RARP:
bpf_error("'rarp' modifier applied to ip6 host");
case Q_ARP:
bpf_error("'arp' modifier applied to ip6 host");
case Q_TCP:
bpf_error("'tcp' modifier applied to host");
case Q_UDP:
bpf_error("'udp' modifier applied to host");
case Q_ICMP:
bpf_error("'icmp' modifier applied to host");
case Q_IGMP:
bpf_error("'igmp' modifier applied to host");
case Q_IGRP:
bpf_error("'igrp' modifier applied to host");
case Q_PIM:
bpf_error("'pim' modifier applied to host");
case Q_VRRP:
bpf_error("'vrrp' modifier applied to host");
case Q_ATALK:
bpf_error("ATALK host filtering not implemented");
case Q_DECNET:
bpf_error("'decnet' modifier applied to ip6 host");
case Q_SCA:
bpf_error("SCA host filtering not implemented");
case Q_LAT:
bpf_error("LAT host filtering not implemented");
case Q_MOPDL:
bpf_error("MOPDL host filtering not implemented");
case Q_MOPRC:
bpf_error("MOPRC host filtering not implemented");
case Q_IPV6:
return gen_hostop6(addr, mask, dir, ETHERTYPE_IPV6,
off_nl + 8, off_nl + 24);
case Q_ICMPV6:
bpf_error("'icmp6' modifier applied to host");
case Q_AH:
bpf_error("'ah' modifier applied to host");
case Q_ESP:
bpf_error("'esp' modifier applied to host");
default:
abort();
}
/* NOTREACHED */
}
#endif /*INET6*/
#ifndef INET6
static struct block *
gen_gateway(eaddr, alist, proto, dir)
const u_char *eaddr;
bpf_u_int32 **alist;
int proto;
int dir;
{
struct block *b0, *b1, *tmp;
if (dir != 0)
bpf_error("direction applied to 'gateway'");
switch (proto) {
case Q_DEFAULT:
case Q_IP:
case Q_ARP:
case Q_RARP:
if (linktype == DLT_EN10MB)
b0 = gen_ehostop(eaddr, Q_OR);
else if (linktype == DLT_FDDI)
b0 = gen_fhostop(eaddr, Q_OR);
else
bpf_error(
"'gateway' supported only on ethernet or FDDI");
b1 = gen_host(**alist++, 0xffffffff, proto, Q_OR);
while (*alist) {
tmp = gen_host(**alist++, 0xffffffff, proto, Q_OR);
gen_or(b1, tmp);
b1 = tmp;
}
gen_not(b1);
gen_and(b0, b1);
return b1;
}
bpf_error("illegal modifier of 'gateway'");
/* NOTREACHED */
}
#endif /*INET6*/
struct block *
gen_proto_abbrev(proto)
int proto;
{
#ifdef INET6
struct block *b0;
#endif
struct block *b1;
switch (proto) {
case Q_TCP:
b1 = gen_proto(IPPROTO_TCP, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_TCP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
case Q_UDP:
b1 = gen_proto(IPPROTO_UDP, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_UDP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
case Q_ICMP:
b1 = gen_proto(IPPROTO_ICMP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_IGMP
#define IPPROTO_IGMP 2
#endif
case Q_IGMP:
b1 = gen_proto(IPPROTO_IGMP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_IGRP
#define IPPROTO_IGRP 9
#endif
case Q_IGRP:
b1 = gen_proto(IPPROTO_IGRP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_PIM
#define IPPROTO_PIM 103
#endif
case Q_PIM:
b1 = gen_proto(IPPROTO_PIM, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_PIM, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
#ifndef IPPROTO_VRRP
#define IPPROTO_VRRP 112
#endif
case Q_VRRP:
b1 = gen_proto(IPPROTO_VRRP, Q_IP, Q_DEFAULT);
break;
case Q_IP:
b1 = gen_linktype(ETHERTYPE_IP);
break;
case Q_ARP:
b1 = gen_linktype(ETHERTYPE_ARP);
break;
case Q_RARP:
b1 = gen_linktype(ETHERTYPE_REVARP);
break;
case Q_LINK:
bpf_error("link layer applied in wrong context");
case Q_ATALK:
b1 = gen_linktype(ETHERTYPE_ATALK);
break;
case Q_DECNET:
b1 = gen_linktype(ETHERTYPE_DN);
break;
case Q_SCA:
b1 = gen_linktype(ETHERTYPE_SCA);
break;
case Q_LAT:
b1 = gen_linktype(ETHERTYPE_LAT);
break;
case Q_MOPDL:
b1 = gen_linktype(ETHERTYPE_MOPDL);
break;
case Q_MOPRC:
b1 = gen_linktype(ETHERTYPE_MOPRC);
break;
#ifdef INET6
case Q_IPV6:
b1 = gen_linktype(ETHERTYPE_IPV6);
break;
#ifndef IPPROTO_ICMPV6
#define IPPROTO_ICMPV6 58
#endif
case Q_ICMPV6:
b1 = gen_proto(IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT);
break;
#endif /* INET6 */
#ifndef IPPROTO_AH
#define IPPROTO_AH 51
#endif
case Q_AH:
b1 = gen_proto(IPPROTO_AH, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_AH, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
#ifndef IPPROTO_ESP
#define IPPROTO_ESP 50
#endif
case Q_ESP:
b1 = gen_proto(IPPROTO_ESP, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_ESP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
default:
abort();
}
return b1;
}
static struct block *
gen_ipfrag()
{
struct slist *s;
struct block *b;
/* not ip frag */
s = new_stmt(BPF_LD|BPF_H|BPF_ABS);
s->s.k = off_nl + 6;
b = new_block(JMP(BPF_JSET));
b->s.k = 0x1fff;
b->stmts = s;
gen_not(b);
return b;
}
static struct block *
gen_portatom(off, v)
int off;
bpf_int32 v;
{
struct slist *s;
struct block *b;
s = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
s->s.k = off_nl;
s->next = new_stmt(BPF_LD|BPF_IND|BPF_H);
s->next->s.k = off_nl + off;
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
b->s.k = v;
return b;
}
#ifdef INET6
static struct block *
gen_portatom6(off, v)
int off;
bpf_int32 v;
{
return gen_cmp(off_nl + 40 + off, BPF_H, v);
}
#endif/*INET6*/
struct block *
gen_portop(port, proto, dir)
int port, proto, dir;
{
struct block *b0, *b1, *tmp;
/* ip proto 'proto' */
tmp = gen_cmp(off_nl + 9, BPF_B, (bpf_int32)proto);
b0 = gen_ipfrag();
gen_and(tmp, b0);
switch (dir) {
case Q_SRC:
b1 = gen_portatom(0, (bpf_int32)port);
break;
case Q_DST:
b1 = gen_portatom(2, (bpf_int32)port);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portatom(0, (bpf_int32)port);
b1 = gen_portatom(2, (bpf_int32)port);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portatom(0, (bpf_int32)port);
b1 = gen_portatom(2, (bpf_int32)port);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_port(port, ip_proto, dir)
int port;
int ip_proto;
int dir;
{
struct block *b0, *b1, *tmp;
/* ether proto ip */
b0 = gen_linktype(ETHERTYPE_IP);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
b1 = gen_portop(port, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portop(port, IPPROTO_TCP, dir);
b1 = gen_portop(port, IPPROTO_UDP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
#ifdef INET6
struct block *
gen_portop6(port, proto, dir)
int port, proto, dir;
{
struct block *b0, *b1, *tmp;
/* ip proto 'proto' */
b0 = gen_cmp(off_nl + 6, BPF_B, (bpf_int32)proto);
switch (dir) {
case Q_SRC:
b1 = gen_portatom6(0, (bpf_int32)port);
break;
case Q_DST:
b1 = gen_portatom6(2, (bpf_int32)port);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portatom6(0, (bpf_int32)port);
b1 = gen_portatom6(2, (bpf_int32)port);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portatom6(0, (bpf_int32)port);
b1 = gen_portatom6(2, (bpf_int32)port);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_port6(port, ip_proto, dir)
int port;
int ip_proto;
int dir;
{
struct block *b0, *b1, *tmp;
/* ether proto ip */
b0 = gen_linktype(ETHERTYPE_IPV6);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
b1 = gen_portop6(port, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portop6(port, IPPROTO_TCP, dir);
b1 = gen_portop6(port, IPPROTO_UDP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
#endif /* INET6 */
static int
lookup_proto(name, proto)
register const char *name;
register int proto;
{
register int v;
switch (proto) {
case Q_DEFAULT:
case Q_IP:
v = pcap_nametoproto(name);
if (v == PROTO_UNDEF)
bpf_error("unknown ip proto '%s'", name);
break;
case Q_LINK:
/* XXX should look up h/w protocol type based on linktype */
v = pcap_nametoeproto(name);
if (v == PROTO_UNDEF)
bpf_error("unknown ether proto '%s'", name);
break;
default:
v = PROTO_UNDEF;
break;
}
return v;
}
static struct block *
gen_protochain(v, proto, dir)
int v;
int proto;
int dir;
{
struct block *b0, *b;
struct slist *s[100];
int fix2, fix3, fix4, fix5;
int ahcheck, again, end;
int i, max;
int reg1 = alloc_reg();
int reg2 = alloc_reg();
memset(s, 0, sizeof(s));
fix2 = fix3 = fix4 = fix5 = 0;
switch (proto) {
case Q_IP:
case Q_IPV6:
break;
case Q_DEFAULT:
b0 = gen_protochain(v, Q_IP, dir);
b = gen_protochain(v, Q_IPV6, dir);
gen_or(b0, b);
return b;
default:
bpf_error("bad protocol applied for 'protochain'");
/*NOTREACHED*/
}
no_optimize = 1; /*this code is not compatible with optimzer yet */
/*
* s[0] is a dummy entry to protect other BPF insn from damaged
* by s[fix] = foo with uninitialized variable "fix". It is somewhat
* hard to find interdependency made by jump table fixup.
*/
i = 0;
s[i] = new_stmt(0); /*dummy*/
i++;
switch (proto) {
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);
/* A = ip->ip_p */
s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
s[i]->s.k = off_nl + 9;
i++;
/* X = ip->ip_hl << 2 */
s[i] = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
s[i]->s.k = off_nl;
i++;
break;
case Q_IPV6:
b0 = gen_linktype(ETHERTYPE_IPV6);
/* A = ip6->ip_nxt */
s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
s[i]->s.k = off_nl + 6;
i++;
/* X = sizeof(struct ip6_hdr) */
s[i] = new_stmt(BPF_LDX|BPF_IMM);
s[i]->s.k = 40;
i++;
break;
default:
bpf_error("unsupported proto to gen_protochain");
/*NOTREACHED*/
}
/* again: if (A == v) goto end; else fall through; */
again = i;
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.k = v;
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
fix5 = i;
i++;
/* if (A == IPPROTO_NONE) goto end */
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_NONE;
s[fix5]->s.jf = s[i];
fix2 = i;
i++;
if (proto == Q_IPV6) {
int v6start, v6end, v6advance, j;
v6start = i;
/* if (A == IPPROTO_HOPOPTS) goto v6advance */
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_HOPOPTS;
s[fix2]->s.jf = s[i];
i++;
/* if (A == IPPROTO_DSTOPTS) goto v6advance */
s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_DSTOPTS;
i++;
/* if (A == IPPROTO_ROUTING) goto v6advance */
s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_ROUTING;
i++;
/* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */
s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*later*/
s[i]->s.k = IPPROTO_FRAGMENT;
fix3 = i;
v6end = i;
i++;
/* v6advance: */
v6advance = i;
/*
* in short,
* A = P[X + 1];
* X = X + (P[X] + 1) * 8;
*/
/* A = X */
s[i] = new_stmt(BPF_MISC|BPF_TXA);
i++;
/* MEM[reg1] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg1;
i++;
/* A += 1 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* X = A */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = P[X + packet head]; */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg2;
i++;
/* X = MEM[reg1] */
s[i] = new_stmt(BPF_LDX|BPF_MEM);
s[i]->s.k = reg1;
i++;
/* A = P[X + packet head] */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_nl;
i++;
/* A += 1 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* A *= 8 */
s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K);
s[i]->s.k = 8;
i++;
/* X = A; */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = MEM[reg2] */
s[i] = new_stmt(BPF_LD|BPF_MEM);
s[i]->s.k = reg2;
i++;
/* goto again; (must use BPF_JA for backward jump) */
s[i] = new_stmt(BPF_JMP|BPF_JA);
s[i]->s.k = again - i - 1;
s[i - 1]->s.jf = s[i];
i++;
/* fixup */
for (j = v6start; j <= v6end; j++)
s[j]->s.jt = s[v6advance];
} else {
/* nop */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 0;
s[fix2]->s.jf = s[i];
i++;
}
/* ahcheck: */
ahcheck = i;
/* if (A == IPPROTO_AH) then fall through; else goto end; */
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*later*/
s[i]->s.k = IPPROTO_AH;
if (fix3)
s[fix3]->s.jf = s[ahcheck];
fix4 = i;
i++;
/*
* in short,
* A = P[X + 1];
* X = X + (P[X] + 2) * 4;
*/
/* A = X */
s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC|BPF_TXA);
i++;
/* MEM[reg1] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg1;
i++;
/* A += 1 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* X = A */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = P[X + packet head]; */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg2;
i++;
/* X = MEM[reg1] */
s[i] = new_stmt(BPF_LDX|BPF_MEM);
s[i]->s.k = reg1;
i++;
/* A = P[X + packet head] */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_nl;
i++;
/* A += 2 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 2;
i++;
/* A *= 4 */
s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K);
s[i]->s.k = 4;
i++;
/* X = A; */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = MEM[reg2] */
s[i] = new_stmt(BPF_LD|BPF_MEM);
s[i]->s.k = reg2;
i++;
/* goto again; (must use BPF_JA for backward jump) */
s[i] = new_stmt(BPF_JMP|BPF_JA);
s[i]->s.k = again - i - 1;
i++;
/* end: nop */
end = i;
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 0;
s[fix2]->s.jt = s[end];
s[fix4]->s.jf = s[end];
s[fix5]->s.jt = s[end];
i++;
/*
* make slist chain
*/
max = i;
for (i = 0; i < max - 1; i++)
s[i]->next = s[i + 1];
s[max - 1]->next = NULL;
/*
* emit final check
*/
b = new_block(JMP(BPF_JEQ));
b->stmts = s[1]; /*remember, s[0] is dummy*/
b->s.k = v;
free_reg(reg1);
free_reg(reg2);
gen_and(b0, b);
return b;
}
static struct block *
gen_proto(v, proto, dir)
int v;
int proto;
int dir;
{
struct block *b0, *b1;
if (dir != Q_DEFAULT)
bpf_error("direction applied to 'proto'");
switch (proto) {
case Q_DEFAULT:
#ifdef INET6
b0 = gen_proto(v, Q_IP, dir);
b1 = gen_proto(v, Q_IPV6, dir);
gen_or(b0, b1);
return b1;
#else
/*FALLTHROUGH*/
#endif
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);
#ifndef CHASE_CHAIN
b1 = gen_cmp(off_nl + 9, BPF_B, (bpf_int32)v);
#else
b1 = gen_protochain(v, Q_IP);
#endif
gen_and(b0, b1);
return b1;
case Q_ARP:
bpf_error("arp does not encapsulate another protocol");
/* NOTREACHED */
case Q_RARP:
bpf_error("rarp does not encapsulate another protocol");
/* NOTREACHED */
case Q_ATALK:
bpf_error("atalk encapsulation is not specifiable");
/* NOTREACHED */
case Q_DECNET:
bpf_error("decnet encapsulation is not specifiable");
/* NOTREACHED */
case Q_SCA:
bpf_error("sca does not encapsulate another protocol");
/* NOTREACHED */
case Q_LAT:
bpf_error("lat does not encapsulate another protocol");
/* NOTREACHED */
case Q_MOPRC:
bpf_error("moprc does not encapsulate another protocol");
/* NOTREACHED */
case Q_MOPDL:
bpf_error("mopdl does not encapsulate another protocol");
/* NOTREACHED */
case Q_LINK:
return gen_linktype(v);
case Q_UDP:
bpf_error("'udp proto' is bogus");
/* NOTREACHED */
case Q_TCP:
bpf_error("'tcp proto' is bogus");
/* NOTREACHED */
case Q_ICMP:
bpf_error("'icmp proto' is bogus");
/* NOTREACHED */
case Q_IGMP:
bpf_error("'igmp proto' is bogus");
/* NOTREACHED */
case Q_IGRP:
bpf_error("'igrp proto' is bogus");
/* NOTREACHED */
case Q_PIM:
bpf_error("'pim proto' is bogus");
/* NOTREACHED */
case Q_VRRP:
bpf_error("'vrrp proto' is bogus");
/* NOTREACHED */
#ifdef INET6
case Q_IPV6:
b0 = gen_linktype(ETHERTYPE_IPV6);
#ifndef CHASE_CHAIN
b1 = gen_cmp(off_nl + 6, BPF_B, (bpf_int32)v);
#else
b1 = gen_protochain(v, Q_IPV6);
#endif
gen_and(b0, b1);
return b1;
case Q_ICMPV6:
bpf_error("'icmp6 proto' is bogus");
#endif /* INET6 */
case Q_AH:
bpf_error("'ah proto' is bogus");
case Q_ESP:
bpf_error("'ah proto' is bogus");
default:
abort();
/* NOTREACHED */
}
/* NOTREACHED */
}
struct block *
gen_scode(name, q)
register const char *name;
struct qual q;
{
int proto = q.proto;
int dir = q.dir;
int tproto;
u_char *eaddr;
bpf_u_int32 mask, addr;
#ifndef INET6
bpf_u_int32 **alist;
#else
int tproto6;
struct sockaddr_in *sin;
struct sockaddr_in6 *sin6;
struct addrinfo *res, *res0;
struct in6_addr mask128;
#endif /*INET6*/
struct block *b, *tmp;
int port, real_proto;
switch (q.addr) {
case Q_NET:
addr = pcap_nametonetaddr(name);
if (addr == 0)
bpf_error("unknown network '%s'", name);
/* Left justify network addr and calculate its network mask */
mask = 0xffffffff;
while (addr && (addr & 0xff000000) == 0) {
addr <<= 8;
mask <<= 8;
}
return gen_host(addr, mask, proto, dir);
case Q_DEFAULT:
case Q_HOST:
if (proto == Q_LINK) {
switch (linktype) {
case DLT_EN10MB:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown ether host '%s'", name);
return gen_ehostop(eaddr, dir);
case DLT_FDDI:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown FDDI host '%s'", name);
return gen_fhostop(eaddr, dir);
default:
bpf_error(
"only ethernet/FDDI supports link-level host name");
break;
}
} else if (proto == Q_DECNET) {
unsigned short dn_addr = __pcap_nametodnaddr(name);
/*
* I don't think DECNET hosts can be multihomed, so
* there is no need to build up a list of addresses
*/
return (gen_host(dn_addr, 0, proto, dir));
} else {
#ifndef INET6
alist = pcap_nametoaddr(name);
if (alist == NULL || *alist == NULL)
bpf_error("unknown host '%s'", name);
tproto = proto;
if (off_linktype == -1 &&
(linktype_af == AF_UNSPEC ||
linktype_af == AF_INET) &&
tproto == Q_DEFAULT)
tproto = Q_IP;
b = gen_host(**alist++, 0xffffffff, tproto, dir);
while (*alist) {
tmp = gen_host(**alist++, 0xffffffff,
tproto, dir);
gen_or(b, tmp);
b = tmp;
}
return b;
#else
memset(&mask128, 0xff, sizeof(mask128));
res0 = res = pcap_nametoaddrinfo(name);
if (res == NULL)
bpf_error("unknown host '%s'", name);
b = tmp = NULL;
tproto = tproto6 = proto;
if (off_linktype == -1 &&
(linktype_af == AF_UNSPEC ||
linktype_af == AF_INET ||
linktype_af == AF_INET6) &&
tproto == Q_DEFAULT) {
tproto = Q_IP;
tproto6 = Q_IPV6;
}
for (res = res0; res; res = res->ai_next) {
switch (res->ai_family) {
case AF_INET:
if (tproto == Q_IPV6)
continue;
if (off_linktype == -1 &&
(linktype_af != AF_INET &&
linktype_af != AF_UNSPEC))
continue;
sin = (struct sockaddr_in *)
res->ai_addr;
tmp = gen_host(ntohl(sin->sin_addr.s_addr),
0xffffffff, tproto, dir);
break;
case AF_INET6:
if (tproto6 == Q_IP)
continue;
if (off_linktype == -1 &&
(linktype_af != AF_INET6 &&
linktype_af != AF_UNSPEC))
continue;
sin6 = (struct sockaddr_in6 *)
res->ai_addr;
tmp = gen_host6(&sin6->sin6_addr,
&mask128, tproto6, dir);
break;
}
if (b)
gen_or(b, tmp);
b = tmp;
}
freeaddrinfo(res0);
if (b == NULL) {
bpf_error("unknown host '%s'%s", name,
(proto == Q_DEFAULT)
? ""
: " for specified address family");
}
return b;
#endif /*INET6*/
}
case Q_PORT:
if (proto != Q_DEFAULT && proto != Q_UDP && proto != Q_TCP)
bpf_error("illegal qualifier of 'port'");
if (pcap_nametoport(name, &port, &real_proto) == 0)
bpf_error("unknown port '%s'", name);
if (proto == Q_UDP) {
if (real_proto == IPPROTO_TCP)
bpf_error("port '%s' is tcp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_UDP;
}
if (proto == Q_TCP) {
if (real_proto == IPPROTO_UDP)
bpf_error("port '%s' is udp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_TCP;
}
#ifndef INET6
return gen_port(port, real_proto, dir);
#else
{
struct block *b;
b = gen_port(port, real_proto, dir);
gen_or(gen_port6(port, real_proto, dir), b);
return b;
}
#endif /* INET6 */
case Q_GATEWAY:
#ifndef INET6
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error("unknown ether host: %s", name);
alist = pcap_nametoaddr(name);
if (alist == NULL || *alist == NULL)
bpf_error("unknown host '%s'", name);
return gen_gateway(eaddr, alist, proto, dir);
#else
bpf_error("'gateway' not supported in this configuration");
#endif /*INET6*/
case Q_PROTO:
real_proto = lookup_proto(name, proto);
if (real_proto >= 0)
return gen_proto(real_proto, proto, dir);
else
bpf_error("unknown protocol: %s", name);
case Q_PROTOCHAIN:
real_proto = lookup_proto(name, proto);
if (real_proto >= 0)
return gen_protochain(real_proto, proto, dir);
else
bpf_error("unknown protocol: %s", name);
case Q_UNDEF:
syntax();
/* NOTREACHED */
}
abort();
/* NOTREACHED */
}
struct block *
gen_mcode(s1, s2, masklen, q)
register const char *s1, *s2;
register int masklen;
struct qual q;
{
register int nlen, mlen;
bpf_u_int32 n, m;
nlen = __pcap_atoin(s1, &n);
/* Promote short ipaddr */
n <<= 32 - nlen;
if (s2 != NULL) {
mlen = __pcap_atoin(s2, &m);
/* Promote short ipaddr */
m <<= 32 - mlen;
if ((n & ~m) != 0)
bpf_error("non-network bits set in \"%s mask %s\"",
s1, s2);
} else {
/* Convert mask len to mask */
if (masklen > 32)
bpf_error("mask length must be <= 32");
m = 0xffffffff << (32 - masklen);
if ((n & ~m) != 0)
bpf_error("non-network bits set in \"%s/%d\"",
s1, masklen);
}
switch (q.addr) {
case Q_NET:
return gen_host(n, m, q.proto, q.dir);
default:
bpf_error("Mask syntax for networks only");
/* NOTREACHED */
}
}
struct block *
gen_ncode(s, v, q)
register const char *s;
bpf_u_int32 v;
struct qual q;
{
bpf_u_int32 mask;
int proto = q.proto;
int dir = q.dir;
register int vlen;
if (s == NULL)
vlen = 32;
else if (q.proto == Q_DECNET)
vlen = __pcap_atodn(s, &v);
else
vlen = __pcap_atoin(s, &v);
switch (q.addr) {
case Q_DEFAULT:
case Q_HOST:
case Q_NET:
if (proto == Q_DECNET)
return gen_host(v, 0, proto, dir);
else if (proto == Q_LINK) {
bpf_error("illegal link layer address");
} else {
mask = 0xffffffff;
if (s == NULL && q.addr == Q_NET) {
/* Promote short net number */
while (v && (v & 0xff000000) == 0) {
v <<= 8;
mask <<= 8;
}
} else {
/* Promote short ipaddr */
v <<= 32 - vlen;
mask <<= 32 - vlen;
}
return gen_host(v, mask, proto, dir);
}
case Q_PORT:
if (proto == Q_UDP)
proto = IPPROTO_UDP;
else if (proto == Q_TCP)
proto = IPPROTO_TCP;
else if (proto == Q_DEFAULT)
proto = PROTO_UNDEF;
else
bpf_error("illegal qualifier of 'port'");
#ifndef INET6
return gen_port((int)v, proto, dir);
#else
{
struct block *b;
b = gen_port((int)v, proto, dir);
gen_or(gen_port6((int)v, proto, dir), b);
return b;
}
#endif /* INET6 */
case Q_GATEWAY:
bpf_error("'gateway' requires a name");
/* NOTREACHED */
case Q_PROTO:
return gen_proto((int)v, proto, dir);
case Q_PROTOCHAIN:
return gen_protochain((int)v, proto, dir);
case Q_UNDEF:
syntax();
/* NOTREACHED */
default:
abort();
/* NOTREACHED */
}
/* NOTREACHED */
}
#ifdef INET6
struct block *
gen_mcode6(s1, s2, masklen, q)
register const char *s1, *s2;
register int masklen;
struct qual q;
{
struct addrinfo *res;
struct in6_addr *addr;
struct in6_addr mask;
struct block *b;
u_int32_t *a, *m;
if (s2)
bpf_error("no mask %s supported", s2);
res = pcap_nametoaddrinfo(s1);
if (!res)
bpf_error("invalid ip6 address %s", s1);
if (res->ai_next)
bpf_error("%s resolved to multiple address", s1);
addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
if (sizeof(mask) * 8 < masklen)
bpf_error("mask length must be <= %u", (unsigned int)(sizeof(mask) * 8));
memset(&mask, 0xff, masklen / 8);
if (masklen % 8) {
mask.s6_addr[masklen / 8] =
(0xff << (8 - masklen % 8)) & 0xff;
}
a = (u_int32_t *)addr;
m = (u_int32_t *)&mask;
if ((a[0] & ~m[0]) || (a[1] & ~m[1])
|| (a[2] & ~m[2]) || (a[3] & ~m[3])) {
bpf_error("non-network bits set in \"%s/%d\"", s1, masklen);
}
switch (q.addr) {
case Q_DEFAULT:
case Q_HOST:
if (masklen != 128)
bpf_error("Mask syntax for networks only");
/* FALLTHROUGH */
case Q_NET:
b = gen_host6(addr, &mask, q.proto, q.dir);
freeaddrinfo(res);
return b;
default:
bpf_error("invalid qualifier against IPv6 address");
/* NOTREACHED */
}
}
#endif /*INET6*/
struct block *
gen_ecode(eaddr, q)
register const u_char *eaddr;
struct qual q;
{
if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
if (linktype == DLT_EN10MB)
return gen_ehostop(eaddr, (int)q.dir);
if (linktype == DLT_FDDI)
return gen_fhostop(eaddr, (int)q.dir);
}
bpf_error("ethernet address used in non-ether expression");
/* NOTREACHED */
}
void
sappend(s0, s1)
struct slist *s0, *s1;
{
/*
* This is definitely not the best way to do this, but the
* lists will rarely get long.
*/
while (s0->next)
s0 = s0->next;
s0->next = s1;
}
static struct slist *
xfer_to_x(a)
struct arth *a;
{
struct slist *s;
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = a->regno;
return s;
}
static struct slist *
xfer_to_a(a)
struct arth *a;
{
struct slist *s;
s = new_stmt(BPF_LD|BPF_MEM);
s->s.k = a->regno;
return s;
}
struct arth *
gen_load(proto, index, size)
int proto;
struct arth *index;
int size;
{
struct slist *s, *tmp;
struct block *b;
int regno = alloc_reg();
free_reg(index->regno);
switch (size) {
default:
bpf_error("data size must be 1, 2, or 4");
case 1:
size = BPF_B;
break;
case 2:
size = BPF_H;
break;
case 4:
size = BPF_W;
break;
}
switch (proto) {
default:
bpf_error("unsupported index operation");
case Q_LINK:
s = xfer_to_x(index);
tmp = new_stmt(BPF_LD|BPF_IND|size);
sappend(s, tmp);
sappend(index->s, s);
break;
case Q_IP:
case Q_ARP:
case Q_RARP:
case Q_ATALK:
case Q_DECNET:
case Q_SCA:
case Q_LAT:
case Q_MOPRC:
case Q_MOPDL:
#ifdef INET6
case Q_IPV6:
#endif
/* XXX Note that we assume a fixed link link header here. */
s = xfer_to_x(index);
tmp = new_stmt(BPF_LD|BPF_IND|size);
tmp->s.k = off_nl;
sappend(s, tmp);
sappend(index->s, s);
b = gen_proto_abbrev(proto);
if (index->b)
gen_and(index->b, b);
index->b = b;
break;
case Q_TCP:
case Q_UDP:
case Q_ICMP:
case Q_IGMP:
case Q_IGRP:
case Q_PIM:
case Q_VRRP:
s = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
s->s.k = off_nl;
sappend(s, xfer_to_a(index));
sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(BPF_MISC|BPF_TAX));
sappend(s, tmp = new_stmt(BPF_LD|BPF_IND|size));
tmp->s.k = off_nl;
sappend(index->s, s);
gen_and(gen_proto_abbrev(proto), b = gen_ipfrag());
if (index->b)
gen_and(index->b, b);
#ifdef INET6
gen_and(gen_proto_abbrev(Q_IP), b);
#endif
index->b = b;
break;
#ifdef INET6
case Q_ICMPV6:
bpf_error("IPv6 upper-layer protocol is not supported by proto[x]");
/*NOTREACHED*/
#endif
}
index->regno = regno;
s = new_stmt(BPF_ST);
s->s.k = regno;
sappend(index->s, s);
return index;
}
struct block *
gen_relation(code, a0, a1, reversed)
int code;
struct arth *a0, *a1;
int reversed;
{
struct slist *s0, *s1, *s2;
struct block *b, *tmp;
s0 = xfer_to_x(a1);
s1 = xfer_to_a(a0);
s2 = new_stmt(BPF_ALU|BPF_SUB|BPF_X);
b = new_block(JMP(code));
if (code == BPF_JGT || code == BPF_JGE) {
reversed = !reversed;
b->s.k = 0x80000000;
}
if (reversed)
gen_not(b);
sappend(s1, s2);
sappend(s0, s1);
sappend(a1->s, s0);
sappend(a0->s, a1->s);
b->stmts = a0->s;
free_reg(a0->regno);
free_reg(a1->regno);
/* 'and' together protocol checks */
if (a0->b) {
if (a1->b) {
gen_and(a0->b, tmp = a1->b);
}
else
tmp = a0->b;
} else
tmp = a1->b;
if (tmp)
gen_and(tmp, b);
return b;
}
struct arth *
gen_loadlen()
{
int regno = alloc_reg();
struct arth *a = (struct arth *)newchunk(sizeof(*a));
struct slist *s;
s = new_stmt(BPF_LD|BPF_LEN);
s->next = new_stmt(BPF_ST);
s->next->s.k = regno;
a->s = s;
a->regno = regno;
return a;
}
struct arth *
gen_loadi(val)
int val;
{
struct arth *a;
struct slist *s;
int reg;
a = (struct arth *)newchunk(sizeof(*a));
reg = alloc_reg();
s = new_stmt(BPF_LD|BPF_IMM);
s->s.k = val;
s->next = new_stmt(BPF_ST);
s->next->s.k = reg;
a->s = s;
a->regno = reg;
return a;
}
struct arth *
gen_neg(a)
struct arth *a;
{
struct slist *s;
s = xfer_to_a(a);
sappend(a->s, s);
s = new_stmt(BPF_ALU|BPF_NEG);
s->s.k = 0;
sappend(a->s, s);
s = new_stmt(BPF_ST);
s->s.k = a->regno;
sappend(a->s, s);
return a;
}
struct arth *
gen_arth(code, a0, a1)
int code;
struct arth *a0, *a1;
{
struct slist *s0, *s1, *s2;
s0 = xfer_to_x(a1);
s1 = xfer_to_a(a0);
s2 = new_stmt(BPF_ALU|BPF_X|code);
sappend(s1, s2);
sappend(s0, s1);
sappend(a1->s, s0);
sappend(a0->s, a1->s);
free_reg(a1->regno);
s0 = new_stmt(BPF_ST);
a0->regno = s0->s.k = alloc_reg();
sappend(a0->s, s0);
return a0;
}
/*
* Here we handle simple allocation of the scratch registers.
* If too many registers are alloc'd, the allocator punts.
*/
static int regused[BPF_MEMWORDS];
static int curreg;
/*
* Return the next free register.
*/
static int
alloc_reg()
{
int n = BPF_MEMWORDS;
while (--n >= 0) {
if (regused[curreg])
curreg = (curreg + 1) % BPF_MEMWORDS;
else {
regused[curreg] = 1;
return curreg;
}
}
bpf_error("too many registers needed to evaluate expression");
/* NOTREACHED */
}
/*
* Return a register to the table so it can
* be used later.
*/
static void
free_reg(n)
int n;
{
regused[n] = 0;
}
static struct block *
gen_len(jmp, n)
int jmp, n;
{
struct slist *s;
struct block *b;
s = new_stmt(BPF_LD|BPF_LEN);
b = new_block(JMP(jmp));
b->stmts = s;
b->s.k = n;
return b;
}
struct block *
gen_greater(n)
int n;
{
return gen_len(BPF_JGE, n);
}
struct block *
gen_less(n)
int n;
{
struct block *b;
b = gen_len(BPF_JGT, n);
gen_not(b);
return b;
}
struct block *
gen_byteop(op, idx, val)
int op, idx, val;
{
struct block *b;
struct slist *s;
switch (op) {
default:
abort();
case '=':
return gen_cmp((u_int)idx, BPF_B, (bpf_int32)val);
case '<':
b = gen_cmp((u_int)idx, BPF_B, (bpf_int32)val);
b->s.code = JMP(BPF_JGE);
gen_not(b);
return b;
case '>':
b = gen_cmp((u_int)idx, BPF_B, (bpf_int32)val);
b->s.code = JMP(BPF_JGT);
return b;
case '|':
s = new_stmt(BPF_ALU|BPF_OR|BPF_K);
break;
case '&':
s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
break;
}
s->s.k = val;
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
gen_not(b);
return b;
}
static u_char abroadcast[] = { 0x0 };
struct block *
gen_broadcast(proto)
int proto;
{
bpf_u_int32 hostmask;
struct block *b0, *b1, *b2;
static u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
switch (proto) {
case Q_DEFAULT:
case Q_LINK:
if (linktype == DLT_ARCNET)
return gen_ahostop(abroadcast, Q_DST);
if (linktype == DLT_EN10MB)
return gen_ehostop(ebroadcast, Q_DST);
if (linktype == DLT_FDDI)
return gen_fhostop(ebroadcast, Q_DST);
bpf_error("not a broadcast link");
break;
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);
hostmask = ~netmask;
b1 = gen_mcmp(off_nl + 16, BPF_W, (bpf_int32)0, hostmask);
b2 = gen_mcmp(off_nl + 16, BPF_W,
(bpf_int32)(~0 & hostmask), hostmask);
gen_or(b1, b2);
gen_and(b0, b2);
return b2;
}
bpf_error("only ether/ip broadcast filters supported");
}
struct block *
gen_multicast(proto)
int proto;
{
register struct block *b0, *b1;
register struct slist *s;
switch (proto) {
case Q_DEFAULT:
case Q_LINK:
if (linktype == DLT_ARCNET)
/* all ARCnet multicasts use the same address */
return gen_ahostop(abroadcast, Q_DST);
if (linktype == DLT_EN10MB) {
/* ether[0] & 1 != 0 */
s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
s->s.k = 0;
b0 = new_block(JMP(BPF_JSET));
b0->s.k = 1;
b0->stmts = s;
return b0;
}
if (linktype == DLT_FDDI) {
/* XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX */
/* fddi[1] & 1 != 0 */
s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
s->s.k = 1;
b0 = new_block(JMP(BPF_JSET));
b0->s.k = 1;
b0->stmts = s;
return b0;
}
/* Link not known to support multicasts */
break;
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);
b1 = gen_cmp(off_nl + 16, BPF_B, (bpf_int32)224);
b1->s.code = JMP(BPF_JGE);
gen_and(b0, b1);
return b1;
#ifdef INET6
case Q_IPV6:
b0 = gen_linktype(ETHERTYPE_IPV6);
b1 = gen_cmp(off_nl + 24, BPF_B, (bpf_int32)255);
gen_and(b0, b1);
return b1;
#endif /* INET6 */
}
bpf_error("only IP multicast filters supported on ethernet/FDDI");
}
/*
* generate command for inbound/outbound. It's here so we can
* make it link-type specific. 'dir' = 0 implies "inbound",
* = 1 implies "outbound".
*/
struct block *
gen_inbound(dir)
int dir;
{
register struct block *b0;
/*
* Only SLIP and old-style PPP data link types support
* inbound/outbound qualifiers.
*/
switch (linktype) {
case DLT_SLIP:
case DLT_PPP:
/* These are okay. */
break;
default:
bpf_error("inbound/outbound not supported on linktype 0x%x\n",
linktype);
/* NOTREACHED */
}
b0 = gen_relation(BPF_JEQ,
gen_load(Q_LINK, gen_loadi(0), 1),
gen_loadi(0),
dir);
return (b0);
}
struct block *
gen_acode(eaddr, q)
register const u_char *eaddr;
struct qual q;
{
if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
if (linktype == DLT_ARCNET)
return gen_ahostop(eaddr, (int)q.dir);
}
bpf_error("ARCnet address used in non-arc expression");
/* NOTREACHED */
}
static struct block *
gen_ahostop(eaddr, dir)
register const u_char *eaddr;
register int dir;
{
register struct block *b0, *b1;
switch (dir) {
/* src comes first, different from Ethernet */
case Q_SRC:
return gen_bcmp(0, 1, eaddr);
case Q_DST:
return gen_bcmp(1, 1, eaddr);
case Q_AND:
b0 = gen_ahostop(eaddr, Q_SRC);
b1 = gen_ahostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ahostop(eaddr, Q_SRC);
b1 = gen_ahostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
}
abort();
/* NOTREACHED */
}
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